The present application relates to D.C.-to-D.C. power converters and, more particularly, to a novel resonant power converter having a relatively high voltage A.C. link section between relatively low D.C. voltage input and output sections.
It is well known to provide a D.C.-to-D.C. power converter utilizing a resonance circuit operating at about the same voltage as the input D.C. voltage. If this input voltage is relatively low, e.g. about 28 volts, then the resonance circuit capacitors operating at this low voltage are physically large and are not volumetrically efficient. If a low input D.C. voltage power supply is operated utilizing a much higher voltage circuit topology, than the resulting resonant capacitor size is excessive and the desired high powered densities cannot be achieved. Further, while high frequency operation is desirable to obtain high efficiency, capacitors suitable for lower-voltage/high-frequency operation are lossy and make it difficult, if not impossible, to obtain high efficiency. Thus, prior art low voltage input resonant circuits utilize resonant components with less than desirable lower power densities and efficiencies. It is highly desirable to provide a resonant power converter which not only operates from a relatively low input D.C. voltage, and provides a relatively low D.C. output voltage, but which also can operate at relatively high frequency and employ more desirable high voltage resonant circuit components.